1. Field of the Invention
The present invention relates to charging equipment for use in a radiotelephone system and, in particular, to equipment for charging a portable terminal in a radio-telephone system.
2. Description of the Related Art
In general, a radio-telephone system includes a fixed terminal and a portable terminal. The fixed terminal is wire-connected to a public switched telephone network. The portable terminal is radio-connected to the fixed terminal, The portable terminal is powered by a rechargeable battery which is mounted within the portable terminal so as to enable various functions of the portable terminal such as telephone speech.
Referring to FIG. 1, a block diagram of conventional equipment for charging a battery which is mounted within a portable terminal 30 of a radio-telephone system is shown. As illustrated, the conventional charging equipment includes an adapter 10 and a charger 20. In order to charge a portable terminal 30 (i.e., charge a battery in the portable terminal 30), the adapter 10 and the charger 20 are connected to each other via a plug 4 and a jack 6 (i.e, the power connector elements). The charger 20, in turn, is connected to the portable terminal 30 via charging terminals 8a, 8b, 8c and 8d.
There are several disadvantages associated with the conventional charging equipment described above. First, the portable terminal 30 can only be charged by using the adapter 10 and the charger 20. Specifically, in order to charge the portable terminal 30, a user is required to connect the adapter 10 and the charger 20 to each other, which results in user inconvenience. Another disadvantage is that the user cannot utilize the portable terminal 30 (i.e., maintain a telephone conversation) while it is being charged since the portable terminal 30 must be connected to the charger 20 via the charging terminals 8a, 8b, 8c and 8d in order to be charged. Due to its connection to portable terminal 30 during the charging process, charger 20 physically prevents the placing or receiving a telephone call. In addition, the adapter 10 which is used for charging the portable terminal 30 is a direct current (DC) adapter (for converting alternating current (AC) voltage to DC voltage) which is very expensive and, therefore, uneconomical.